This invention relates to an electro-optical device utilizing a liquid crystal display device wherein non-linear elements composed of Metal-Insulator-Metal (MIM) elements are arranged in a matrix corresponding to picture display cells.
Recently, liquid crystal display devices have found wide spread use in many fields including applications in wrist watch and electronic calculator technology. These devices employ flat type display units and can be driven at low voltages, thus requiring low power consumption. However, when these devices are employed in information display terminals or small hand-held electronic equipment there are some disadvantages. These display devices yield an image with relatively poor contrast regardless of the level of the driving voltage. In addition, the resolution and capacity of displayed information in any one picture frame is limited due to the inability to multi-digit matrix drive the display.
In order to eliminate these disadvantages and increase the amount of information that can be shown on any one frame, non-linear elements, such as MIMs, can be used conjunction with the liquid crystal display device. In the prior art, each MIM element is constructed by anodyzing the surface of a Ta film pattern and forming a Cr pattern thereon. Using this construction, a metal-insulator-metal element is formed by layering in the vertical direction at the junction of the overlapping Ta pattern and Cr pattern.
In the conventional MIM element, the overlapping portion of the Ta film with the Cr pattern becomes a separate region and the size of the region is limited by the minimum area that the pattern forming method requires. The limit in practical terms is a ten micrometer square. Therefore, the actual size of the picture element cannot be further reduced and this makes it difficult to improve display resolution capacity.
Accordingly, it is desirable to provide a MIM element which overcomes these problems of the prior art and reduces in the size of the MIM element.